Transport device and printing device

Abstract

Provided are a transport device and a printing device configured to minimize fluctuation in a tension of a medium in a portion between a first transport unit and a second transport unit. A transport device provided to a printing device includes a transport mechanism serving as an example of the first transport unit, a winding unit serving as the second transport unit disposed downstream of the transport mechanism in a transport direction, a tension imparting unit provided with a tension bar serving as an example of a tension imparting member biased toward a medium between the transport mechanism and the winding unit and configured to impart tension to the medium, and a biasing force adjustment unit serving as an adjustment unit configured to adjust at least one of a biasing force of the tension bar and a relative speed between the tension bar and the medium.

The invention claimed is: 
     
       1. A transport device comprising:
 a first transport unit; 
 a second transport unit disposed downstream of the first transport unit in a transport direction; 
 a tension imparting unit provided with a tension imparting member biased toward a medium between the first transport unit and the second transport unit and configured to impart tension to the medium; 
 an adjustment unit configured to adjust at least one of a biasing force of the tension imparting member and a relative speed between the tension imparting member and the medium; and 
 a detector configured to detect the tension imparting member approaching the medium when a distance therebetween is less than or equal to a distance threshold value, wherein 
 when the detector detects the approach, the adjustment unit adjusts a relative speed between the tension imparting member and the medium to be less than a relative speed obtained when adjustment is not performed. 
 
     
     
       2. The transport device according to  claim 1 , wherein the detector is provided to the tension imparting member. 
     
     
       3. The transport device according to  claim 1 , wherein the detector is of contact type implementing detection by contacting with the medium. 
     
     
       4. The transport device according to  claim 1 , wherein when the detector detects the tension imparting unit and the medium approaching each other so that a distance therebetween is less than or equal to the distance threshold value, the adjustment unit adjusts the relative speed by controlling the second transport unit. 
     
     
       5. The transport device according to  claim 1 , wherein
 the adjustment unit includes a biasing force adjustment unit configured to adjust a biasing force of the tension imparting member, and 
 when the detector detects the tension imparting member and the medium approaching each other so that a distance therebetween is less than or equal to the distance threshold value, the biasing force adjustment unit adjusts the biasing force of the tension imparting member to be smaller in comparison with a biasing force obtained when adjustment is not performed. 
 
     
     
       6. The transport device according to  claim 5 , wherein when the detector detects the tension imparting member and the medium approaching each other so that a distance therebetween is less than or equal to the distance threshold value, the biasing force adjustment unit imparts a braking force to the tension imparting member. 
     
     
       7. The transport device according to  claim 1 , wherein the detector includes a tension imparting member position acquiring unit configured to acquire a position of the tension imparting member, and a medium position acquiring unit configured to acquire a position of the medium, and detects the tension imparting member and the medium approaching each other so that a distance therebetween is less than or equal to the distance threshold value, based on the position of the tension imparting member acquired by the tension imparting member position acquiring unit and the position of the medium acquired by the medium position acquiring unit. 
     
     
       8. The transport device according to  claim 1 , wherein
 the adjustment unit includes a biasing force adjustment unit configured to adjust a biasing force of the tension imparting member, and 
 when the detector detects the tension imparting member and the medium approaching each other, the biasing force adjustment unit adjusts the biasing force of the tension imparting member to be smaller. 
 
     
     
       9. The transport device according to  claim 8 , wherein the detector is of contact type implementing detection by contacting with the medium. 
     
     
       10. The transport device according to  claim 8 , wherein the biasing force adjustment unit is a braking force generating unit configured to generate in the tension imparting unit a braking force in a direction of reducing the biasing force. 
     
     
       11. The transport device according to  claim 10 , wherein the braking force generating unit generates the braking force by applying a load to the tension imparting unit,
 the load being obtained by any one of a driving force of a drive source, a frictional load, a viscous load, an elastic load, and a center-of-gravity shift of the tension imparting unit. 
 
     
     
       12. The transport device according to  claim 10 , wherein the braking force generating unit is configured to adjust the braking force generated in the tension imparting unit. 
     
     
       13. The transport device according to  claim 12 , wherein the braking force generating unit changes the braking force in accordance with a position of the tension imparting member when the first transport unit starts transporting the medium. 
     
     
       14. A printing device comprising:
 the transport device according to  claim 1 ; and 
 a printing unit configured to perform printing on the medium transported by the transport device. 
 
     
     
       15. A transport device comprising:
 a first transport unit; 
 a second transport unit disposed downstream of the first transport unit in a transport direction; 
 a tension imparting unit provided with a tension imparting member biased toward a medium between the first transport unit and the second transport unit and configured to impart tension to the medium; 
 an adjustment unit configured to adjust at least one of a biasing force of the tension imparting member and a relative speed between the tension imparting member and the medium; and 
 a detector configured to detect the tension imparting member approaching the medium when a distance therebetween is less than or equal to a distance threshold value, wherein 
 the adjustment unit includes a biasing force adjustment unit configured to adjust a biasing force of the tension imparting member, and 
 when the detector detects the tension imparting member and the medium approaching each other, the biasing force adjustment unit adjusts the biasing force of the tension imparting member to be smaller.